Manufacture or production of hollow concrete floors, beams, and slabs



May 18 1926. 1 585,430

H. F. SMITH ET AL MANUFACTURE OR PRODUCTION OF HOLLOW CONCRETE FLOORS,BEAMS, AND SLABS Filed August 28 1925 ll/III/IIII IIIJIIIIIIIIIIIIIIIIIIIIII Patented May 18, 1926.

UNITEQ S'E'Alfitii meant earner assist.

HORACE FRANK SMITH, OF LONDON, AND CHARLES HERBERT TUCKWELL, OF RICI-I-I MOND, ENGLAND.

MANUFACTURE OR PRODUCTION OF HOLLOW CONCRETE FLOORS, BEAMS, AND SLABS.

Application filed August 28, 19535. Serial No. 53,020.

This invention relates to improvements in the manufacture or productionof hollow concrete floors, beams and slabs, and particu larly toimprovements in the cores employed in such structures and articles ofmanufacture, whereby such cores may be transported in flat sheets andreadily made up into rigid box-like cores for use on the building siteor elsewhere as required.

It has before been proposed to construct hollow concrete floors, beamsor the like, by casting concrete around cores or matrices of tile,timber or metal. These cores or matrices have been costly in themselvesand bulky in transport and have required skilled labour or appliancesfor their formation into box-like form. It has also been proposed tostrengthen such hollow concrete beams by means of metal hoops orstirrups and main reinforcing bars.

Now, according to the present invention, the cores which are to beemployed in the production of concrete floors, beams, slabs and thelike, are composed of sheets of fibrous material such as fibre-board,papier-mach, cardboard, millboard or the like of requisite dimensionsaccording to the shape and size of the cavity or cavities to be producedin the concrete slab. Such sheets are scored in parallel lines on oneside of the sheet, so as to render them foldable into the required formof the core with great ease and without calling for the exercise ofskilled labour. Such sheets may therefore be foldable into boxlike form.

During the operation of manufacturing a hollow concrete floor, beam orslab by means of cores formed in accordance with the present invention,the cores are located upon a base of concrete, which is previously laidto a sufficient depth, and then concrete is filled around the sides ofthe cores thus forming webs and over the tops of the cores to therequired thickness.

lWith sheets scored to facilitate folding on such lines, by turning thesaid sheet inwards at each scoring line to an angle of about 90, ab0x-like core is produced which may be rigidly maintained in position bymeans of metal hoops or stirrups, which latter may be utilized to securethe main reinforcing bars of the concrete floor, beam or slab.

Each sheet of fibre-board may be conveniently folded say three times toproduce a core of box-like section, but'it is to be particularlyunderstood that the invention is not limited to the form of thissection. The ends of the box-like core may also be closed by auxiliaryfolded flaps, and these will stiffen the core.

The invention will be further described with reference to theaccompanying drawings, in which,

Fig. 1 is a cross section of a portion of a hollow concrete floorconstructed according to this invention.

Fig. 2 is a longitudinal section on the line AB of Fig. 1, and

Fig. 3 is a transverse section of a hollow beam or slab.

Referring to the drawings, 1 is the concrete forming the shell of thefloor, beam or slab, and 2 is the core of fibre-board, papierunach,cardboard, millboard or the like around which the concrete is cast.

The core sheets are scored or creased in predetermined positionsindicated at 3, to enable them to be readily and accurately foldableinto box-like form from flat sheets.

Metal hoops or stirrups a maintain the cores rigidly in box-like form,and such hoops or stirrups have loops at the lower corners provided tolocate the main reinforcing bars 5 of the floor, beam or slab.

To form the scored sheets 2 into box-like cores, each sheet is foldedupon the scored or indented lines 3 to an angle of about 90 (see Fig.1), and wire hoops or stirrups 4 placed around the folded sheet to holdthe scored sheet rigidly in its folded box-like formation. Vhenreinforcing bars 5 are used in the concrete structure, the hoops orstirrups t may also encircle the bars 5 by loops at the corners tosecure them in position. The ends of the box-like core may be closed byfolding inwards the ends of the sheet 2 as indicated at 2 in Fig, 2, bywhich means additional stiffening of the core is obtained.

In this way a rigid core may be produced at the building site fromsheets of fibrous material sent out flat for facility and economy oftransport.

During the operation of manufacturing a hollow concrete floor, beam orslab by 1 means of cores formed in accordance with the presentinvention, the cores are located upon a base of concrete, which ispreviously laid to a sufficient depth, and then concrete is filledaround the sides of the cores thus forming vertical webs and over thetops of the cores to the required t-h'ckness, thus producing a hollowconcrete floor, beam or slab of required section.

What we claim as our invention and dcsire to secure by Letters Patentis 1. A concrete floor, beam, or slab, com prising in combination coresof folded fibrous material scored within the folds, a concrete layerlocated below the cores, conc1 ete webs at the sides of the cores, :1concrete layer above the cores, metal hoops around the cores, and formedwith loops at the lower corners thereof and metal rein- 15 forcing barslocated in the loops.

2. A concrete floor, beam, or slab, comprising in combination cores offolded fibrous material scored within the folds, a concrete layerlocated below the cores concrete webs at the sides of the cores, aconcrete layer above the cores, metal hoops around the cores, formedwith loops at the lower corners thereof and metal reinforcing barshaving their ends upturned and located in the loops.

In witness whereof we have hereunto set our hands.

HORACE F. SMiTl-l. CHARLES HERBERT TUCKWELL.

